Climate Change: The Real Deal

The Economist had an interesting piece on climate science this week which is attracting some attention. The article reaffirmed, yet again, that greenhouse gases are changing our climate in dangerous ways. But it also pointed to a scientific puzzle: that warming may not have advanced in the last decade as much as current models predicted, given the amount of emissions the world has produced.

My main take-away is that the article underscores the fundamental nature of climate change -- that we are creating dangerous uncertainties. (As you can imagine, some of the usual suspects are using questions about the details of climate science to deny climate change entirely. Never mind that the Economist article is quite clear that the issues raised in no way alter the fact that greenhouse gas pollution is disrupting our climate.)

In fact, no one knows for sure how much damage we are doing through our large-scale changes to the natural world. To my mind, that uncertainty is a powerful reason for taking remedial action now – not only because there are a range of actions that will pay off under virtually any probable scenario, but also because action now keeps open the option to do more later if the science warrants it.

We know there are dangerous climate disruptions coming. So, regardless of how quickly it gets hotter, we need to stop making investment decisions that make things worse, like building power plants that produce a lot of pollution. We need to base our decisions on the big scientific picture, which shows that climate is being changed by pollution, and not the evolving predictions of how much and how fast this is happening.

Of course, if the climate is warming a little more slowly than we thought, that would be great news. Given that we haven’t yet implemented a comprehensive strategy to combat warming, slower warming would buy us time. But at best that’s a little like hearing “the earthquake that’s coming may only be a 6.7, not a 7.3” or “the disease may spread through the population a little more slowly than we thought.”

We need to be open to the possibility that the Economist is right. Honest scientific inquiry should never rule out new ideas. The experts at Climate Nexus, though, point to a few potential problems with the science in the piece. They note that a growing number of studies have documented heat being redirected into the ocean instead of the atmosphere; and that the selection of a 15-year timeframe incorrectly compares current atmospheric temperatures with those of an anomalously warm El Niño period. They also raise the issue of ongoing research into aerosols (fine particulate matter in the atmosphere), which show it may be obscuring atmospheric warming we would otherwise see.

Being an academic by training, I can't help but add a few questions of my own. First, the article and the studies it draws on may be making too much out of what is a short and recent trend. Using just the last ten years of climate data is probably misleading, since it is dominated by a few relatively cool years. It still seems hard to believe that we can infer a lot about long-term equilibrium climate sensitivity from a handful of data points. The longer-term trends are quite clear.

Second, some of what is going on appears to be disagreement among different types of climate models. A careful reading of the piece reveals that the low-end estimates of climate sensitivity are coming from one particular type of model (top-down or “energy balance” models), which are highly simplified and potentially influenced too much by recent data. The more complex bottom-up models tend to suggest higher sensitivities – that is, more warming.

Third, as the article itself points out, the link between concentration and temperature rise is only part of the story. Relative to projections of just a few years ago, emissions are increasing faster than expected in most of the world (even if they may be leveling off in the United States). On the current trajectory, even if the climate sensitivity is “only” 2 degrees, we will still have more than 2 degrees of warming – getting well into the region where science suggests we will start to see significant adverse impacts on the climate system.

Given that we are already seeing severe impacts (increased incidence of drought, extreme weather, etc.) linked to the warming observed so far, the effect of even modest temperature increases could be worse than we thought. Indeed, even if the studies about climate sensitivity are correct, the implications for policy are not so clear-cut. As the Economist article points out, actual policies lag well behind what we think is needed. Even with a lower climate sensitivity, we would need to step up our policies – for example, by putting a price on carbon pollution, as the last paragraph of the article suggests we must do.

The article raises an interesting scientific question, which is always good. But it is worrisome that some people are already ignoring the nuances of the piece and misusing it to confuse the public. The real message, as the article says, is that even if they’re right, it “does not mean the problem is going away.” I hope people take the time to read and digest the whole piece; it would be too bad if most readers walked away thinking that this means we don’t need to do anything about climate change.

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Comments

Great article that conjures up as many questions as it answers.
How do we put a massive push on EV's and if we were all driving one, would it help?

How do we get the developing nations reinvest in less polluting energy producing technologies when the west has been the maim culprit for so many decades.

Is it too late? Has too much damage been done to reverse anything?

jim priebe

April 2, 2013at 7:46 pm (ET)

Global warming ideas are based on mathematical models. How well do models predict the economy? Or day to day weather?
We need something better than models to serve as a basis for committing billions of dollars as a countermeasure.
I vote for data.

Dan

April 2, 2013at 9:35 pm (ET)

This is a crazy day for Google News! All bull! There is a big difference between a 6.7 and a 7.3 earthquake (log scale). This guy is advising the Prez!
While you have the correct attitude about climate change, taking action is very painful.
The article would have been more interesting as an insider of the WH.

Willie Tucker

April 3, 2013at 1:22 am (ET)

Nice article, but your statement "Given that we are already seeing severe impacts (increased incidence of drought, extreme weather, etc.) linked to the warming observed so far" is a little fuzzy in the cause and effect link. Sure, we see extreme weather now, but only because we are in the present and don't have complete information 200 years ago. Or, even how can anyway prove that the extreme weather is created from other sources unrelated to warming.

Furthermore, how does any scientist know what is "normal"? Or how have improvements in the measuring devices used to measure temperature impact the results? Or how can temperature readings in just a few parts of the world create a true picture? Scientists can't explain why there was an ice age 4000 years ago, and yet they expect us to shell out billions of dollars to stop global warming, and make USA the poorest nation on earth as it drives all manufacturing out of our country, because of a political agenda not shared throughout the world? Who side are these scientists on?

Man

April 3, 2013at 3:23 am (ET)

The precautionary principle is simply not scientifically rigorous. There is no way that forcing global commitment to uneconomic energy choices will lead to a prosperous and healthy future. Windmills are a poor substitute for existing efficient energy sources; we build them where the highest winds have always governed massive migration routes for natural flight. Solar panels are inefficient and manipulated by opportunistic contractors who cannot provide the technology to small homeowners. Both source of energy are erratic and disrupt the base load required to operate an efficient grid. Worst of all, the rush to react to the perceived fear of carbon is driven by alarmist propaganda and hurts the poor first.

There is no threat because warming and cooling are already evidence of the balance of nature. When heating from any source (even the sun)occurs, humidity increases, cloud cover increases and precipitation cools. The extremes we observe are simply the ineffable balance of nature on a planet that has achieved equilibrium over 4.8 billion years of experiment; never static but never overreacting within livable limits to which mankind, a newcomer, must adapt, not alter. CO2 is plant food.

Dawn

April 3, 2013at 6:14 pm (ET)

CO2 is essential to plants, however, if we continue deforestation, mountaintop removal and the sort then there will be no plants to absorbs CO2 emissions. What are we to do then? Just wait? Do we continue to let large corporations to monopolize and extract such oils, coals etc so we can be dependent on them for energy? We, as a people are stewards to planet earth. If we keep doing what we are currently doing at the rate at which we do consume where population is growing, well, it will be devestating to humankind and all ecosystems. We can no longer wait , need to implement alternatives and spark ideas for lower CO2 emissions.

Hugh Jacz

April 5, 2013at 8:17 pm (ET)

In a situation of even relatively low probability, if the consequences of the event would be catastrophic a rational person buys insurance. The probability that climate change is real is above relatively low. If it's real, it will be catastrophic. The insurance in this case does not hurt the economy but allows it to compete into the future.

Two facts are irrefutable: 1) current CO2 levels are higher than they've ever been during human history 2) CO2 is a greenhouse gas.

You want to just ignore the possibilities? You aren't behaving rationally.

James Singmaster, III, Ph.D.

April 10, 2013at 2:14 pm (ET)

Nothing will save the future for our children except one Action and that is TO MAKE THE SUN OUR SOLE ENERGY SOURCE.
We are fooling ourselves with numerous nonsense proposals and actions. Geoengineering is total nonsense, CCS is baloney, Growing biofuels is just plain fuelishness(WHY CAN'T EDF RECOGNIZE THAT BIOWASTES ARE AN ALREADY HARVESTED FOREVER BIOFUEL SUPPLY). I have posted comments on various blogs(Yale's e360, NRDC's Switchboard, UCS's The Equation and here in the past) stating that we have TO MAKE THE SUN OUR SOLE ENERGY SOURCE. If anyone at EDF can dispute that action with some other more effective action to get control of CC/GW, I challenge him to state it. Dr. J. Singmaster, III, Environmental Chemist, Ret.